I argue that a variety of influential accounts of self-knowledge are flawed by the assumption that all immediate, authoritative knowledge of our own present mental states is of one basic kind. I claim, on the contrary, that a satisfactory account of self-knowledge must recognize at least two fundamentally different kinds of self-knowledge: an active kind through which we know our own judgments, and a passive kind through which we know our sensations. I show that the former kind of self-knowledge is in an important sense fundamental, since it is intimately connected with the very capacity for rational reflection, and since it must be present in any creature that understands the first-person pronoun. Moreover, I suggest that these thoughts about self-knowledge have a Kantian provenance.